We knew Adele had broken a sales record for her newest album, "25," but her sales also far outpaced those of the band that previously sold the most records in a week.

Adele's album "25" sold 3.38 million copies in its first week, far surpassing NSYNC's 2000 album "No Strings Attached," which held the record for most album sales in a week after selling 2.416 million albums at that time.

Thus Adele holds the record for most albums sold in a week since Nielsen started examining these numbers in 1991.

Adele's work was released on Nov. 20 and so is of course expected to do well during the holiday shopping season as well as during 2016. Adele's previous album "21," for example, became the bestselling album of both 2011 and 2012 after being released in 2011.

How did Adele do this? Her album sales were most likely helped by the decision by her and her team to keep "25" off services like Spotify and Apple Music. If "25" wasn't available on streaming, fans who wanted to hear it badly enough most likely decided to purchase a copy, helping the album's sales. ("25" is available on the radio program Pandora – music by artists like Adele becomes available there automatically.)

In addition, there was demand for her music. "21" became a huge smash and there was a four-year gap in between Adele's albums. By comparison, artists that had some of the bestselling albums of the year in recent years like Taylor Swift and One Direction have released two and four albums since 2011, respectively.

In 2012, Adele's "21" sold more copies in England than Michael Jackson's "Thriller." "25" could do the same, especially as "25" has a bigger head start – "21" sold only 352,000 copies in its first week (that's an "only" by Adele standards).

These are numbers that are increasingly rare in the music industry, where album sales are affected by illegal downloads and streaming services. By comparison, Swift's "1989," the top-selling album of 2014, sold 3.66 million copies that year.

Adele's success may be due to a combination of factors: her vocal prowess shows her genuine talent, her songs have a retro mood that gives them a wide appeal, and her album not appearing on streaming services means consumers have fewer places where they can find it.